Pharmacological Evaluation of the Bronchorelaxant Effect of Waltheria Indica L

Hindawi Evidence-Based Complementary and Alternative Medicine Volume 2021, Article ID 5535727, 8 pages https://doi.org/10.1155/2021/5535727 Research Article Pharmacological Evaluation of the Bronchorelaxant Effect of Waltheria indica L. (Malvaceae) Extracts on Rat Trachea Rainatou Boly ,1 Zakaline Yabre,2 Mathieu Nitiema ,1 Boubacar Yaro,1 Jules Yoda,1 Lazare Belemnaba ,1 Sylvain Ilboudo,1 Noe¨la Hoho Estelle Youl,2 Innocent Pierre Guissou,3 and Sylvin Ouedraogo1 1Institute of Research in Health Science (IRSS), 03 PO 7047, Ouagadougou 03, Burkina Faso 2Laboratory of Drug Development, Doctoral School of Sciences and Health, University Joseph KI-ZERBO, 03 BP 7021, Ouagadougou 03, Burkina Faso 3University of Saint 0omas D’Aquin, 06 PO 10212, Ouagadougou 06, Burkina Faso Correspondence should be addressed to Rainatou Boly; [email protected] Received 21 January 2021; Revised 10 April 2021; Accepted 15 April 2021; Published 27 April 2021 Academic Editor: Vincenzo De Feo Copyright © 2021 Rainatou Boly et al. 'is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Waltheria indica L. (Malvaceae) is a plant used in Burkina Faso for the treatment of various ailments including asthma. 'e aim of the study was to evaluate the pharmacological relaxant effect of the leafy stem extracts of Waltheria indica and thereby verify claim of use in treating asthma. Aqueous decoction and hydroalcoholic extracts obtained from the powdered leafy stems were screened for the presence of some phytoconstituents. 'e in vitro relaxant effect of the two extracts was evaluated on acetylcholine- (ACh 10−5 M) and potassium chloride- (KCl 6 ×10−2 M) induced contractions on rat-isolated tracheal preparations. To examine whether the potassium (K+) channels are involved in the relaxant effect, glibenclamide, an ATP-sensitive potassium channel inhibitor, was used. Moreover, to assess the safety of the extracts, acute oral toxicity was carried out on mice. 'e phytochemical screening revealed the presence of alkaloids, flavonoids, saponins, steroids, triterpenoids, tannins, and coumarins in the hydroalcoholic extract. Tannins, steroids, triterpenoids, and coumarins were not detected in the aqueous decoction. With re- spective EC50 values of 1.517 ± 0.002 mg/mL and 1.433 ± 0.001 mg/mL on ACh-and KCl-provoked contractions, the hydroalcoholic extract was found more potent in relaxing the isolated rat tracheal preparations compared to the aqueous decoction. In the presence of glibenclamide, the relaxant effect of the hydroalcoholic extract (EC50 � 0.191 ± 0.002 mg/mL) increased and was higher than that of the aqueous decoction. At dose of 5000 mg/kg of body weight, the extracts did not produce deaths or any significant changes in the general behavior of mice. 'e results suggest that different mechanisms including modulation of calcium and potassium channels, particularly the ATP-sensitive K+ channels, could be involved in the relaxation effect. 'ese findings could justify the traditional use of W. indica in the management of asthma. 1. Introduction asthma affects more than 339 million persons, both children and adults, across the world regardless the level of devel- Asthma is a heterogenous disease characterized by multiple opment [2]. 'e prevalence of asthma varies from 1 to 18% factors involving genetic predisposition and environmental worldwide and the disease mostly affects poor children and factors [1–3]. It is one of the most common chronic diseases people among the general population [5, 9]. In fact, about that present different features including bronchocon- 250 000 deaths from asthma occur mostly in low- and striction, airway hyperreactivity, mucus secretion, and middle-income countries [2, 10]. Few studies have been chronic inflammation [4–6]. Asthma symptoms include dedicated to the study of asthma in Africa as reported by episodes of wheezing, coughing, and breath shortness [7–9]. Adeloye et al. [10]. In their report, the number of asthma 'e World Health Organization (WHO) estimates that cases is estimated at 119.3 million in 2010 [10]. Asthma 2 Evidence-Based Complementary and Alternative Medicine represents a public health problem that is underdiagnosed W. indica has many other names. Hence, it is called “Nal- and undertreated, with the consequence of increasing the labenda” in Telugu, “kafafi” in Fulani, “hankubath” in disease burden, mainly in least developed countries Hausa, “korikodi” in Yoruba, “matum kevel” in Wolof, “yar- [2, 9, 10]. yamde” in Moore, “Mokhutesela” in South Africa, “guinar¨ ” According to the Global Initiative of Asthma (GINA), in Mexico, “uhaloa” in Hawaii, and “malvavisco” in Spanish the treatment of asthma aims to control symptoms in order [22]. Waltheria indica is a short-lived shrub reaching 2–7 m to minimize risk of exacerbations [1]. Numerous com- height and a stem diameter of 2 cm. 'e plant is widely pounds have been developed for the management of asthma. present in subtropical and tropical regions and can grow on 'ese compounds act to (i) reverse or prevent bronchial many areas including roadside weed, old pastures, inun- smooth muscle constriction and (ii) reverse or prevent dated savannas, or riverbanks [23, 24]. Different parts of this airway inflammation [11]. 'e current approach to the plant are customarily used to treat diverse ailments in- treatment of asthma consists of using corticosteroids (oral cluding pain, cancer, inflammation, cough, sore throat, lung and inhaled) associated with bronchodilators (short- and infections, and asthma [23, 25–27]. Ethnobotanical data long-acting beta 2-agonists), leukotriene antagonists, and gathered from traditional healers confirmed the use of the long-acting anticholinergics [6, 7, 9, 12]. Nevertheless, de- aerial parts, roots, and whole plant of Waltheria indica to spite the fact that most current antiasthmatic drugs have treat asthma in Burkina Faso [16]. Preclinical studies in- proven to be effective, the need to develop or search for new dicated that Waltheria indica and its active compounds ones is necessary. Indeed, the current asthma drugs are exhibited analgesic, anti-inflammatory, cancer chemo- associated with the occurrence of several side effects preventive effect, antioxidant, antidiabetic, antiviral, anti- [6, 13, 14]. For instance, the long use of inhaled cortico- bacterial, bronchorelaxant, and other potential steroids may be accompanied by bronchitis, nasophar- pharmacological activities [23, 25, 28–31]. 'e pharmaco- yngitis, and respiratory tract infection while the common logical effect of W. indica is based on the presence of nu- adverse effects of anticholinergic drugs (beta-2-agonists) are merous bioactive compounds such as tannins, flavonoids, urinary tract infection, dyspnea, headache, cough, and terpenes, alkaloids, carbohydrates, sterols, cardiac glyco- nausea [14]. Furthermore, these drugs are sometimes not sides, and anthraquinones [22]. accessible to many patients, mainly in poor countries, due to Few reports have been dedicated to the study of the use their high cost. 'e annual management of asthma in terms of Waltheria indica L. for the management or treatment of of both direct and indirect costs in Europe and United States asthma. 'erefore, the present study was undertaken to of America is approximately estimated at €18 billion and investigate the pharmacological relaxant effect of the leafy US$13 billion, respectively [3]. According to a recent report stem extracts of Waltheria indica on rat trachea. Further- on the economic burden of asthma, annual direct costs more, this study aims to provide an attempt to explain the varied from US$150 to US$3,000 per patient [15]. In 2005, mechanism of the bronchorelaxant action. the annual treatment of a moderate asthma costed approximately US$192 in Burkina Faso [16]. Due to the several 2. Materials and Methods drawbacks associated with the conventional treatment of asthma, the development of novel therapeutic approaches 2.1. Chemicals and Reagents. All chemicals and reagents effective at low cost and with low side effects will alleviate used to carry out the experiments were of analytical grade. asthma patients. Acetylcholine was purchased from Sigma-Aldrich (St. Louis, 'e use of phytomedicine or traditional herbal medi- MO). Potassium chloride (KCl) was supplied by Labosi cines is one of these approaches. Herbal medicines are (France). Tablets of 5 mg glibenclamide (Tongmei, Togo) widely used worldwide due to their important health benefits were purchased at a local pharmacy in Ouagadougou, capital combined with reduced adverse effects and toxicity city of Burkina Faso. Dichloromethane, n-hexane, and [3, 17–19]. Indeed, according to the WHO, at least 80% of butanol were obtained from Carlo-Erba (France). Ethanol African populations rely on traditional herbal medicine for and ethyl acetate were procured from Prolabo (France). their primary healthcare due to its accessibility and af- Silica gel TLC plates F 254 grade were from Macherey-Nagel fordability [17, 19, 20]. (Germany). Several authors reported the large and successful use of herbal medicine among both adults and children suffering from asthma [3, 7, 18, 21]. However, despite these significant 2.2. Equipment. 'e apparatus used to achieve the bron- findings, it is noteworthy that the pharmacological valida- chorelaxant effect of extracts from leafy stems of Waltheria tion of a number of these plant-derived medicines still

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